The present invention relates generally to automotive fuel systems, and more particularly, to a fuel pressure regulator.
In automotive vehicles, the fuel supplied to the engine is pressurized before being fed to the engine. Typically, automotive fuel is stored unpressurized in a fuel tank. Through a series of pumps, valves and fuel lines, the fuel system then pressurizes the fuel to a final pressure before introducing the fuel to the engine. The final pressure of the fuel, however, is closely controlled to ensure proper performance of the engine.
Commonly, automotive fuel systems use a conventional fuel pressure regulator in at least one stage of fuel pressurization. The fuel pressure regulator may be located within the fuel tank of the vehicle, although the regulator may be located elsewhere in the fuel system. Typically, high pressure fuel is supplied to the fuel pressure regulator from a pump powered by a DC motor. The pressure level of the fuel supplied by the pump usually fluctuates. One reason for these pressure fluctuations is that the voltage supplied to the DC motor varies depending on the loads applied to the vehicle""s electrical system and temperature and pressure changes in the fuel delivery system. The fuel pressure regulator removes these pressure fluctuations by introducing a pressure drop and supplying an output fuel line with lower pressure fuel with a generally constant pressure level.
Conventional fuel pressure regulators are usually preset by the manufacturer to provide a single pressure level at the output line. This is often achieved by calibrating a bias valve, such as a spring valve, during assembly of the fuel system. Although these systems are relatively inexpensive and simple to assemble, they are unable to provide variable pressure levels at the output line. As the demand for fuel efficiency and higher performance has increased, a need now exists for fuel systems that can provide variable fuel pressure depending on the operating conditions of the vehicle. Moreover, it is desirable to provide electronic control of the fuel system so the vehicle""s central processing unit can automatically adjust the fuel pressure.
One alternative fuel system involves providing a brushless DC motor with speed control circuitry to power the fuel pump. A pressure sensor is also provided to monitor the pressure level of the fuel exiting the fuel pump. Thus, by monitoring the pressure level with the pressure sensor, the vehicle""s central processing unit can adjust the speed of the motor to achieve the desired fuel pressure. The problem with this alternative is the high cost of the system compared to conventional fuel systems. For example, the brushless DC motor with speed control circuitry is more expensive than the standard DC motor used in conventional systems. An expensive pressure sensor is also required which is unnecessary in conventional systems. In addition, this alternative fuel system is more complicated and difficult to assemble than conventional fuel systems.
The present invention is defined by the following claims, and nothing in this section should be taken as a limitation on those claims. By way of introduction, the embodiments described below include an electronically controlled continuous, fuel pressure regulator that produces more than one fuel pressure. The fuel pressure regulator includes an input line, an output line and a pressure plate that restricts fuel from passing from the input line to the output line. A spring is provided for resisting movement of the pressure plate. A coil, armature and casing or head pole are also provided for further resisting movement of the pressure plate. When electric current is supplied to the coil, a magnetic force attracts the armature toward the casing- or head pole.
Different embodiments of the fuel pressure regulator are provided. One embodiment includes a connecting tube. In this embodiment, the spring is compressed by the connecting tube when electric current is supplied to the coil. In other embodiments, a shaft is connected to the pressure plate and to the armature. In these embodiments, the armature resists movement of the pressure plate when electric current is supplied to the coil.